A range of N‐methyliminodiacetic acid (MIDA) boronates of commercially available but unstable ortho‐phenolboronic acid derivatives can be readily prepared through simple condensation between the corresponding phenolboronic acids and MIDA in the presence of molecular sieves. The resulting MIDA boronates are bench‐top stable and display a remarkable stability even in DMSO solution at high temperature (>120 °C) compared with their parent boronic acids. Moreover, the utility of the resulting MIDA boronate was successfully demonstrated in a cross‐coupling reaction using the slow‐release protocol to afford the cross‐coupled product in much better yield compared with its parent boronic acid counterpart. In addition, an alternative, but more efficient, synthetic route for difficult‐to‐access ortho‐phenol MIDA boronates has been developed through the MIDA boronate formation of methoxymethyl (MOM) protected ortho‐phenolboronic acid, followed by deprotection of the MOM group with TMSCl under ambient conditions.
